It looks like a new "locally integrated menu" will make it into Unity, starting with version 5.6.0. There's basically no information about the new locally integrated menubar, except for two bug reports which link to some custom Unity, Compiz, Metacity and Light Themes branches so to see "LIM" in action, I've compiled all these branches and here's the result. The "locally integrated menubar" can be displayed on the panel (for maximized windows) as well as in the window decoration (unmaximized windows). But it's not displayed on both in the same time.

I love the menubars at the top of the screen. Are those called "global" menubars? I don't know the terminology. Of couse I'm a Mac guy so I love the way Mac OS X does it. That's also the reason I Ubuntu on some of my machines. Go go Mac style menubars!